The present invention relates in general to driver operator controls in a mobile vehicle such as a car, truck, train, bus, or airplane, and, more specifically, to touchscreen control panels with haptic feedback.
A typical transportation vehicle such as a car or truck includes many operator-controlled systems and accessories. In order to handle the diverse interactions with vehicle electronic systems such as a climate control system, media and entertainment system, driver information system, navigation system, or wireless communication system, a centralized control panel interface may be provided on the vehicle dashboard or instrument panel. Such a centralized unit can result in ease of use and lowering overall manufacturing costs. One common type of human-machine interface involves the use of a touchscreen for displaying different context-sensitive menus with various graphical elements associated with the controlled features or systems for manipulation by the user's fingers in order to adjust various parameters of the associated electronically-controlled systems.
The ease of use and the amount of time required for making appropriate selections are important considerations for vehicle design in order to limit the potential driver distraction associated with use of the controls. It is desired to avoid driver distraction that might result when using a touchscreen by having to visually search for a desired feature or zone on the touchscreen and then having to wait for a confirmation that a desired control action has been executed in response to a user's touch command. Furthermore, road-induced vibration and rocking motions of the user's body can affect the ability to accurately place or slide a finger on a touchscreen in the intended locations. Further, sun load on the screen may hamper the driver's ability to see the screen function icons clearly.
Voice commands and synthesized speech responses are sometimes used in an attempt to avoid these issues, but it can be difficult to accurately detect and characterize speech in a noisy vehicle environment and often the driver may not know or recognize the proper key words that must preface certain audible commands.
Automotive touchscreen controls are known which provide haptic feedback by mechanically moving (e.g., vibrating) the surface of the touchscreen in association with activation of a particular command (see, e.g., U.S. Pat. No. 7,834,857 and U.S. Pat. No. 8,269,726). Haptic vibration requires a motor, solenoid, or piezoelectric device to produce mechanical vibration of the touchscreen, thereby imposing significant limitations upon the touchscreen technologies and materials that can be used. Such systems are also subject to mechanical wear and failures, and they produce undesirable noise when activated.
A new type of haptic feedback for touchscreens has become available based upon the principle of electrovibration to create tactile sensations based on electrostatic friction between a touchscreen surface and a user's finger (without any actual vibration of the touchscreen). For example, a system known as Tesla-Touch has been described (see., e.g., U.S. patent application publication 2012/0327006) employing a transparent electrode disposed over the touchscreen for interacting with a moving finger that slides over the transparent electrode, wherein a periodic electrical signal is applied between the electrode and finger to induce an attractive force by an electric field that is modulated to vary the friction in a desired manner such that when the finger is moved across the screen surface in the presence of the modulation, and resulting variable friction, the friction pattern will simulate the feeling of different textures. For example, a sinusoidal modulation may feel like a wavy surface and a square wave modulation may feel like parallel lines or ridges. Although not described in connection with context-sensitive menus or other automotive control panels, changing the texture of a tactile feedback while dragging an adjustment slider has been suggested for use in graphical user interfaces (GUIs). However, no system has yet been shown or suggested for using varying textures in navigating context-sensitive menus which would be very helpful for navigating automotive controls with reduced need for visual attention.